Posted: 06 October 2008
Scientific breakthrough in young neutron star research
With the assistance of the ‘Watcher’ robotic telescope which was designed, built and is operated by staff and students from the UCD School of Physics, a team of international scientists has uncovered new ways of understanding young neutron stars.
The findings, published in the leading scientific journal Nature, show how, over the course of three days, a source, believed to be a neutron star, experienced 40 optical flares before disappearing.
Initially the bizarre source – SWIFT J195509+261406 - misled its discoverers. It first showed up as a gamma-ray burst, pointing to a stellar death in the distant universe. However soon after, it exhibited unique behaviour which indicates its origin in our own galaxy, the Milky Way. After the initial gamma-ray pulse there was a three-day activity period during which 40 optical flares were observed followed by a brief near-infrared flaring episode 11 days later.
Pictured far right: Artist’s view of a soft gamma-ray burst arising from a magnetar (image courtesy of NASA)
According to the scientists involved, the main difficulty in studying this source is that it hibernates for decades before entering a brief period of activity. Following the observations, the source is now believed to be a young neutron star. These stars are created following a supernova explosion inside a massive star somewhere between 8 and 15 times the mass of the sun, which has expelled its outer layers following the explosion. They are made up of a very dense, solid crust and an inner core filled mostly with neutrons.
“Although small, ‘Watcher’, which is located in South Africa, can re-orient itself very quickly and in this case, re-pointed to the new source 23 seconds after receiving the information via the internet, only 53 seconds after the source discovery at gamma-ray energies by the NASA Swift satellite,” says Dr Lorraine Hanlon from the UCD School of Physics. “As the larger more sensitive telescopes require longer times to change their pointing direction, Watcher obtained unique coverage of 6 of the flaring episodes, including one where the brightness increased by a factor of 100 in 2 minutes.”
The international research team, led by scientists at the Astrophysical Institute of Andalucía, is composed of 42 scientists who used data taken by 8 telescopes worldwide. One of the co-authors of a separate Nature paper devoted to this source, UCD graduate Dr Sheila McBreen will be joining the UCD School of Physics staff in November 2008.
Initial funding for the ‘Watcher’ telescope project was provided by IRCSET and the project is currently funded by SFI.
